The present invention relates to an ink refilling unit used to refill ink into an ink container which stores the ink to be delivered to a recording head, an ink refilling method, and an ink jet apparatus comprising a refillable ink container and an ink refilling unit. In particular, it relates to an ink refilling system capable of effectively and reliably refilling even an ink container which is integrally and removably mountable on a recording head comprising a plurality of ink storing portions.
Recently, in the field of ink jet recording, an ink jet unit in the form of a cartridge, which integrally comprises a recording head and an ink container, has been used from the standpoint of size reduction, maintenance reduction, and the like. This ink jet unit is easily mountable on the scanning carriage of an apparatus, or is easily removable from the carriage. Further, when the ink in the ink container is completely depleted, the ink jet unit can be easily exchanged with a fresh ink jet unit.
On the other hand, there are high demands for colorization of record. As for the structure currently in use for meeting the above colorization demands using an ink jet unit as described above, there are a few structures for recording in color. For example, in one structure, record is made in color by a plurality of color ink jet units parallelly disposed on a carriage in the scanning direction. In another structure, record is made in color by a color ink jet unit and a black ink jet unit, which are also disposed on the carriage. In the case of the latter structure, the color ink jet unit integrally comprises an ink container for yellow ink, an ink container for magenta ink, an ink container for cyan ink, and a corresponding number of recording heads for ejecting these color inks.
However, the above structures had a problem in that a recording head still usable when the ink in an ink jet unit is completely depleted had been discarded. Therefore, in recent years, a few proposals have been made to solve this problem. According to one of these proposals, the recording head and the ink container are rendered separable.
Thus, it has been proposed to refill the ink container of such an ink jet unit with refill ink. More specifically speaking, according to the system of Graphic Utilities Co., Ltd., a metallic hypodermic needle attached to a bellows type ink supply container is inserted into a hole made in an ink depleted ink container, and the ink in the bellows type ink supply container is injected into the ink depleted ink container as pressure is gradually applied by manually collapsing the bellows type ink supply container. There is also a structure in which the bellows type ink supply container is replaced by a syringe, and the ink is pressure fed into the ink depleted ink container in a manner to give an injection.
The ink refilling methods described above has the following problems. First, since they are manual methods, there are many occasions in which excessive pressure is applied by the operator. As excessive pressure is applied, ink delivery speed exceeds the speed at which the delivered ink permeates into the absorbent member in the ink depleted ink container. As a result, ink drips from the needle tip without being injected into the container. Further, since it is impossible to know the exact amount of ink to be refilled, only way to know whether the ink container is completely filled or not is to wait until ink begin to overflow from the hole made in the ink depleted ink container. Secondly, since a needle must be handled to manually inject ink, the operator is sometimes injured. Thirdly, in order to refill ink without spilling it, it is required to maintain a proper amount of pressure, complicating the structure for satisfying such a requirement. Fourthly, since the pressure necessary to refill ink is manually generated, the time which the operator has to spend to refill ink becomes rather long. Fifthly, before the needle is inserted into the ink depleted ink container, the ink supply container of the bellows type or the hypodermic syringe type is rather sensitive to pressure, and therefore, slight impact causes ink to leak from the needle. Sixthly, when discarding an ink refilling kit, it has to be disassembled into individual components, which are separated according to material type, when it is discarded.
It is conceivable that the ink container opening, which is connected to the recording head, be used to refill ink into the removable ink container of the above described ink jet unit. But, as long as the aforementioned bellows type ink refilling kit or the like is used, the problems described in the foregoing remain. In particular, since the container opening, which is to be connected to the recording head, is substantially larger than the diameter of the needle of the ink refilling apparatus, the ink leakage related problem becomes a matter of more serious concern.
Japanese Laid-Open Patent Application No. 1,744/1995 discloses an ink filling apparatus of a different type. This apparatus comprises an ink cartridge (ink container) and a chamber for storing ink, and fills ink with the use of a capillary element. However, in this apparatus, the path through which ink is delivered when printing, and the section in which ink is filled, are different. Therefore, a sponge member and the capillary element must be pressed against each other to reliably fill ink. This creates two regions different in compression ratio, a region closer to the printing head, and a region closer to where ink is filled. When an attempt is made to refill ink into a completely ink depleted ink container of this type, air is taken into the region between these two differently compressed regions. As a result, it sometimes becomes impossible to continuously carry out printing. Further, when the sponge member and the capillary element are pressed against each other before the ink is completely depleted, ink leaks sometimes as the sponge member is squeezed.
Moreover, in the case of the structure disclosed in Japanese Laid-Open Patent Application No. 1,744/1995, the capillary element is rather long, increasing flow resistance. As a result, it takes a substantially longer time to fill. Also, as the ink within the refill ink chamber decreases, the internal pressure of the refill in chamber decreases. Consequently, the chamber reacts to suck in air. But, since there is no place where air can flow in, ink filling is interrupted. These are the additional problems.
Based on the knowledge and observation described above, the inventors of the present invention have already proposed an ink refilling method and an ink refilling apparatus, which do not have the aforementioned weaknesses. This ink refilling method is used in conjunction with an ink container of a specific type. That is, the ink container has an ink absorbent portion adjacent to the ink delivery port to which an ink recording head is connected, and contains a porous member which generates negative pressure within the container, wherein at least a part of the initially filled ink is consumed through the ink absorbent portion adjacent to the joint portion. This ink refilling method is characterized in that it comprises a step in which the ink meniscus at the ink absorbent portion of the ink container is destroyed, and a step in which the refill ink is filled into the ink depleted ink container by the negative pressure generated by the porous member through the ink consumption from the ink container. As for the essential point of the characteristic, the negative pressure generated through the consumption of the ink held by the porous member within the ink container is used to reliably refill the ink container with ink, without overfilling, that is, while preventing the ink from spilling out of the ink container. Preferably, ink should be refilled from the side from which the ink within the ink container is delivered to the recording head. Such an arrangement assures that ink is reliably refilled into the ink container to prevent the interruption of the ink delivery to the recording head.
Compared to the conventional method, the ink refilling method described in the foregoing can further improve on operational efficiency. More specifically, since the conventional ink refilling method employs only an unsophisticated filling device, the user has to hold both the ink container and the filling device at the same time, and therefore, it is low in operational efficiency. Such inefficiency can be eliminated with the use of the ink -refilling apparatus and the ink refilling method, which were described in the foregoing paragraph, so that ink is prevented from overflowing, and above all, ink can be refilled into the ink container in a manner to render the condition of the refilled container substantially the same as that of a freshly opened ink container.
More specifically, the above ink refilling system which is used in conjunction with an ink container for an ink recording head, in which an ink absorbent member is disposed in the ink delivery port connectible to an ink recording head, and in which an ink retaining member formed of porous material capable of generating internal negative pressure is disposed, comprises: a section for holding the ink recording head; a means for holding the refill ink for the ink container as well as delivering the refill ink to the ink absorbent member of the ink container; and a means disposed on the ink delivering means to destroy the meniscus of the ink absorbent member, wherein after the ink within the ink absorbent member is united with the ink retained in the ink delivering means, by the meniscus destroying means, the ink container is filled with the refill ink by the negative pressure induced through the ink consumption from the ink container.
The above described process (or means) for destroying the ink meniscus means any process (or means) capable of uniting the remaining ink in the ink container with the refill ink by destroying at least a part of the meniscus formed by the internal negative pressure of the ink container; for example, positive pressurization of the refill ink, or negative pressurization of the internal space of the ink container. A preferable means is the following one: the meniscus is destroyed by inserting a rod-like member, having a very small sectional area and being constituted of stands of fiber arranged to provide microscopic gaps, into the ink absorbent member, along with the refill ink which permeates the rod-like member due to capillarity.
Regarding the ink refilling system described above, the ink absorbent member of the ink container is positioned at a lower level in terms of the gravitational direction than the porous member of the ink container so that the refill ink is delivered upward from below. With this arrangement, the refill ink can be reliably filled into the ink container through the ink delivery port of the ink container. Further, according to the above described system, the ink absorbent member composed of strands of fiber unidirectionally bundled to improve ink delivery efficiency with which ink is delivered from the ink container to the recording head is also used on the refill mechanism side; therefore, the refill ink is more uniformly filled into the ink container. In particular, in the case of an ink container from which ink is delivered downward (preferably, straight downward) to the ink recording head when recording, the ink remaining in the ink container uniformly settles on the ink delivery port side; therefore, such an ink container can function more efficiently.
The above invention is also applicable to an ink container comprising a plurality of sub-containers for holding different inks. In the case of such an application, all the sub-containers are filled with the aforementioned porous material, and their ink delivery ports provided with their own absorbent ink delivery members are disposed on the same side of the ink container. Further, each sub-container is filled with refill ink by its own refill ink delivering means through the aforementioned absorbent ink delivery member. With this provision, each sub-container can be simply and reliably filled with the refill ink, to a predetermined ink level of its own, without color mix-up and without being overfilled.
The present invention was made to improve the above described ink refilling method and ink refilling apparatus, that is, to render them more cost effective, simpler to use, and more reliable.
In other words, the primary object of the present invention is to provide an ink refilling apparatus which requires only a simple step of mounting an ink container in the ink refilling apparatus to quickly fill the ink container with the refill ink, without the need for a dangerous member such as an ink injecting needle, and also is capable of preventing ink leakage, and preventing the user from being tied up for a long time to refill the ink container.
More specifically, the primary object of the present invention is to reliably unite the remaining ink in the ink container used with an ink recording head container, with the refill ink for the ink container, wherein the ink container has an ink absorbent ink delivery member in the ink delivery port which is connected to the ink recording head, and an ink retaining member formed of porous material capable of inducing negative pressure in the ink container, in the ink storage chamber. The second object is to quickly fill up the ink container by minimizing the flow resistance in the path through which the refill ink is filled into the ink container.
According to an aspect of the present invention, there is provided an ink refilling apparatus, comprising: an ink absorbing member at a connecting portion relative to an ink recording head; an ink container holding portion to which an ink container for the ink recording head provided with a porous ink retaining member capable of producing a negative pressure therein, is mountable; an ink discharging means for accommodating the ink to be refilled into the ink container and supplying the ink to the ink absorbing member of the ink container; wherein after the ink of the ink absorbing member and the ink retained by the ink discharging means are contacted to each other, the ink is refilled using a negative pressure produced by consumption of the ink from the ink container; the improvement residing in that ink absorbing member having substantially the same property as the ink absorbing member of the ink container is provided at an ink container connection side of the ink discharging means, the ink absorbing members are contacted to each other upon mounting of the ink container, by which a meniscus formed at a contact surface of the ink absorbing member, is broken.
The inventors of the present invention reconfirmed based on the above observation that the conventional ink refilling process for an ink jet recording apparatus was controlled by external factors such as the capacity of the ink delivery mechanism of the ink refilling system, and therefore, the process was liable to be hindered by excessive or insufficient external force, and that currently, when an ink container which contained the ink absorbent member composed of porous material (being at least partially compressed, or entirely compressed to half or quarter the precompression size) was filled with ink for the first time, ink was forcefully filled into the ink absorbent member by reducing the internal pressure of the ink container. Also during the above observation, they discovered a phenomenon that as ink was consumed from the ink absorbent member filled with ink, the absorbent member developed a substantial amount of negative static pressure, that is, the sum of minute negative static pressure induced in each microscopic pores of the ink absorbent member. Thus, they realized that using this phenomenon for refilling the ink container is the most rational way to refill the ink container, and made the present invention which made it possible to reliably refill the ink container regardless of the amount of the ink remaining in the ink container, without causing an ink overflow.
Thus, according to the present invention, a method for refilling an ink container containing a porous member capable of generating negative pressure within the ink container, after at least a portion of the initially filled ink is consumed, is characterized in that it comprises a step in which the ink meniscus formed in the ink container, on, or adjacent to, the portion to be connected to a recording-head, is destroyed, and a step in which the refill ink is filled into the ink container due to the negative pressure which the porous member develops as the ink is consumed therefrom, while maintaining contact between the refill ink and the joint portion.
Also, a method for refilling an ink container in which an ink absorbent member is disposed on, or adjacent to, the portion to be connected to a recording head, and a porous member capable of generating negative pressure within the ink container is disposed in the ink storing portion, after at least a portion of the initially filled ink is consumed, is characterized in that it comprises a step in which the ink meniscus formed in the ink container, on, or adjacent to, the portion to be connected to a recording head, is destroyed, and a step in which the refill ink is filled into the ink container due to the negative pressure which the porous member develops as the ink is consumed therefrom, while maintaining contact between the refill ink and the joint portion.
The gist of the present invention is to use the negative pressure generated as the ink retained in the porous member of the ink container is consumed, to reliably refill the ink container, without overfilling or causing an ink overflow. Further, it is most desirable that the refill ink is filled into the ink container through the side through which ink is delivered to the recording head portion. This is because such an arrangement can prevents interruption of ink flow, and therefore, can most reliably refill the ink container.
The above described process (or means) for destroying the ink meniscus means any process (or means) capable of uniting the remaining ink in the ink container with the refill ink by destroying at least a part of the meniscus formed by the internal negative pressure of the ink container; for example, positive pressurization of the refill ink, or negative pressurization of the internal space of the ink container. A preferable means is the following one: the meniscus is destroyed by inserting a rod-like member, having a very small sectional area and being constituted of stands of fiber arranged to provide microscopic gaps, into the portion to be connected to the recording head, the adjacencies of the portion, or the ink absorbent member, along with the refill ink which upwardly permeates the rod-like member due to capillarity.
Regarding the ink refilling system described above, the ink absorbent member of the ink container is positioned at a lower level in terms of the gravitational direction than the porous member of the ink container so that the refill ink is delivered upward from below.
Further, according to the present invention, the ink absorbent member composed of strands of fiber unidirectionally bundled to improve ink delivery efficiency with which ink is delivered from the ink container to the recording head is also used on the refill mechanism side. In particular, in the case of an ink container from which ink is delivered downward (preferably, straight downward) to the ink recording head when recording, the remaining ink in the ink container evenly settles on the ink delivery port side; therefore, such an ink container can function more efficiently.
In the case of the present invention structured as described above, when the refill ink is filled into the ink container, an ink reception member which is formed of porous material and is compressed against an ink absorbent member which is formed of porous material and is disposed in the ink container to retain ink, and a first ink delivery member which is composed of porous material and is disposed in a refilling mechanism for delivering the refill ink into the ink container, are pressed against each other, whereby the refill ink stored in the refilling mechanism is delivered into the ink container.
Since the refill ink is delivered into the ink container by the negative pressure generated by the porous material, it is unnecessary to reduce the internal pressure of the ink container by a pump or the like, and also, external ink leakage does not occur. Further, the refilling of the ink container is triggered by destroying the meniscuses of the ink absorbent ink reception member and the ink absorbent delivery member by placing the two absorbent members directly in contact with each other; therefore, it is possible to provided an inexpensive but highly reliable ink refilling apparatus.
Further, the ink absorbent member of an ink delivery means, which is disposed on the side which faces the ink container, is rendered substantially equal in size to the ink absorbent member of the ink container, or is rendered smaller in density than the ink absorbent member of the ink container; therefore, the flow resistance of the ink path is minimized. As a result, it takes only a short time to completely refill the ink container.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.